1. Field of the Invention
The present invention relates to an air type solar system that utilizes solar energy, where the air being heated by solar heat is provided as a heat source to heat air and water in a home or the like for heating, humidification, hot-water supply, and so on.
2. Description of the Related Art
Heretofore, technologies for utilizing solar heat have been studied and developed in the art. In the first half of 1980s shortly after the oil shocks, however, the technical developments were at their peaks. After that time, they are almost stagnant.
Among these technologies, water-heating type solar systems, which utilize solar heat, have been relatively used in common. However, they hardly attain performance goals such as anti-freeze, caulking, and increased useful life of durability.
Among them, on the hand, air-heating type solar systems are suited to be distributed over wide areas including cold regions because they are free of troubles such as freezing and water leakage. However, they consume more electric energies, which are comparatively expensive, and the volumetric specific heat of air is 0.3/1000. Therefore, a more volume of airflow should be supplied for collecting the desired amount of solar heat.
Furthermore, a solar system used for heating in a building has a disadvantage of being brought down at the time of power fails in disaster situations or the like. When a ventilation device is operated in some way even at the time of power failure to allow heat function, it will become possible to utilize a solar system in a disaster, refugee camps, and so on irrespective of nations and places.
Therefore, it has been desired to solve the problems in technical development for using heat from solar energy and enhancing the progress of such a technical development. In addition, it has been also desired to progress the technical development of self-sustaining operation of the solar system at the time of power fails.
In U.S. Pat. No. 5,849,107 (1998), for example, a solar system disclosed in JP-B-No. 48299/1991 is exemplified as one of the conventional technologies. In other words, the air-heating type solar system is presented for utilizing a clean energy source, in which solar heat is collected using the surface of a roof board and is then utilized for floor heating, hot-water supply, and the like.
In the system, as shown in FIG. 26, fresh air enters an air passage 3 formed on a roof plate 1 through an outside air inlet 2. The outside air inlet 2 is formed at the edge of eaves and rises naturally and gradually toward the ridge of a roof. The air passing through the air passage 3 becomes warmer by receiving solar heat radiated to the roof surface through the roof plate 1 provided as a heat-collecting metallic roof plate.
Then, the warm air is supplied to a space 6 formed under a floor via an air duct 5 by a blower fan 4, thereby to heat the entire space of a room 7. The air passage 3 and the air duct 5 are covered with a heat insulating material 8 in order to prevent heat from escaping.
In U.S. Pat. No. 5,849,107 (1998), therefore, there is proposed a method of using a solar cell, which is one of the existing clean energy sources, as a power source of the above system, where a solar cell module made up of a plurality of solar cells is used in place of a metallic heat-collecting plate on the roof.
Furthermore, such a heat collector using the conventional solar cell to be used in the above process of heating or humidification is mainly designed such that the solar cell is used in combination with a storage cell. In this case, the storage cell may be used for the power supply by converting the generated electricity to a solar cell into an alternating current power supply and the stabilization of power-supply voltage to directly use the solar cell as a power source. In addition, it may be used for the operation in darkness or at night without power generation from the solar cell or used as an auxiliary power supply with respect to a control power supply.
However, lead-containing storage cells generally used in large quantities are inferior in durability and contain substances that have adverse environmental effects. Therefore, the use of such storage cells should be avoided as far as possible.
Furthermore, for example, a method of switching to a storage cell provided as an auxiliary power-supplying device when the decrease in electric power generated from a solar cell is caused, a method of stabilizing the power using such an auxiliary power-supplying device, or the like requires a complicated configuration of building blocks. It may become difficult to use the electric power generated from the solar cell the most effectively.
For the collection of heat using a solar cell, on the other hand, a pump for transferring water is used in a water-type solar system and a fan for transferring air is used an air-type solar system. In these cases, however, there is no consideration given to an electrical control of the amount of flow, in particular completely none in small and domestic devices, because of the following reasons.
In a solar system such as a water-type solar system, a heat medium for heating circulates through a heat-collecting portion and a hermetically sealed heat-storage tank to perform a heat exchange. Therefore, the main reason is that an efficiency of collecting heat increases as the amount of flow being circulated increases, so that there is no need of flow control. In the air-type solar system, furthermore, there is no need of flow control just as in the case with the water-type one when the heat exchange is performed by circulating through a semi-hermetically sealed heat-storage tank using crushed stones or the like.
Another reason is that there is a blind spot in the generally considered air-flowing properties of pump or fun to be driven by a solar cell. The production of electricity from the solar cell is in proportion to the; amount of solar radiation, so that it is considered that a heat-collecting temperature may decrease as the airflow increases in summer, while the heat-correcting temperature may increase as the airflow decreases in winter. Such a blind spot may be depended on that the necessity of controlling the amount of flow in the conventional heat-collecting system as described above.
Regarding the actual power-generating properties of the solar cell, a substantial decrease in the amount of electricity production, especially the voltage of generated power is caused in summer. Therefore, the flow rate of air or water passing through the pump or fan, which is driven by the solar cell, is decreased in summer. In this case, furthermore, the temperature of heat-collected air can be extremely increased. Such a blind spot is generated because of the following reasons. That is, the performance of the solar cell is rated at a standard temperature of 25xc2x0 C., so that there is a large difference between the maximum temperature of the solar cell and the standard temperature (25xc2x0 C.) in summer (i.e., approximately 70 to 80xc2x0 C.) while a small difference between the maximum temperature of the solar cell (i.e., approximately 10 to 40xc2x0 C.) and the standard temperature (25xc2x0 C.) in winter.
Generally, the solar system is required to provide a large quantity of airflow in summer and a small quantity of airflow in winter. However, the airflow properties of the fan to be simply driven by a solar cell are reversed from the desired airflow.
An object of the present invention is to provide an air type solar system having the advantages of: solving the above disadvantages of the conventional systems described above in quest of an effective use of solar cells and displacement of storage cells and obviating the need for storage cells; and appropriately controlling the operation of a blower fan that receives electric power supplies mainly from the solar cells such that the temperature of heat-collected air is not too high in summer while it is adjusted within the desired range in winter.
For attaining the above object, In a first gist of the present invention, there is provided an air type solar system, comprising: a heat-collecting unit for heating air by solar heat; and blower fan for blowing the air as a heat medium from the heat-collecting unit, wherein the blower fan is of a large scale, which is capable of: blowing the air at a rate of about 100 to 2000 m3/hour; and rotating by a direct-current generated from solar cells under normal conditions, while the amount of airflow is confined by an automatic electrical control in winter to adjust the temperature of heat-collected air to an appropriate temperature for heating or humidification.
In a second gist of the present invention, the electrical control may be performed by detecting the temperature of heat-collected air by a temperature sensor, and generating an output signal of a degree of a proportional control to an integrated circuit of a fan-driving motor controller, where the degree of the proportional control is obtained from the difference between the temperature of heat-collected air and a target temperature to be attained by the CPU.
In a third gist of the present invention, a damper may be placed in an air passage through which the air is supplied from the blower fan, where the damper can be fixed in a predetermined state by a gear lock or the like even after powering off.
In a fourth gist of the present invention, the automatic electrical control is exercised by a control device having a nonvolatile memory that keeps the contents, the contents of matters detected by the temperature sensor, the determining status of the control, and so on.
In a fifth gist of the present invention, the solar cell is connected with an auxiliary power-supplying device via a rectifying device, where the auxiliary power-supplying device is adjusted to a voltage lower than an appropriate operating voltage thereof to be obtained by providing the solar cell as the power-supplying device, and a combination of the solar cell and the auxiliary power-supplying device is used as a power-supplying device.
In a sixth gist of the present invention, the heat-collecting unit for heating air by solar heat is mounted on a roof, a wall, or the like, and is communicated with a heat-collecting duct, while the heat-collecting duct is connected with a backflow-preventing dumper for preventing backflow of air to the heat-collecting duct, a passage-switching dumper for switching between an airflow to a vertical dumper for flowing the air into a room and an airflow to an exhaust duct for exhausting the air outside, and a handling box having a blower fan arranged between the backflow-preventing damper and the passage-switching damper, and the output side of the handling box is connected with the vertical duct for flowing the air into the room and the exhaust duct for exhausting the air outside.
According to the invention of claim 1, in the operation of the air type solar system, the electric power generated by solar cells is used as an electric power supply to increase the dependency on natural energy that can be recycled. Therefore, there is an advantage of ensuring the minimum heating conditions by its self-sustaining at a distant location, or in the event of a power failure or disaster, so that it can be useful to keep the safety of life and property from dangerous matters and deficiencies.
Next, the air type solar system of the present invention does not use any storage cell, so that the durability thereof can be increased. By the way, in the case of a system that uses a typical commercial power supply, especially one using an unstable power supply from solar cells or the like, a storage cell is generally mounted for storing a comparatively large amount of electric power to keep the operation of switching devices such as dumpers, settings of the operation, information about the control, the actuation of the blowing fan, and so on. However, such a system has many problems that should be solved. For instance, the lifetime of the storage cell such as a lead-acid battery is short. In addition, there is the need for control management on the charged voltage for preventing deterioration of the charging performance. Furthermore, there is another problem that the storage cell contains an environmentally toxic substance that cannot be discarded. According to the present invention, on the other hand, these problems can be solved.
Furthermore, according to the present invention, the air type solar system has the blower fan that mainly uses the power supplied from solar cells. Therefore, such a fan is able to appropriately adjust the airflow to a strong one in summer and a weak one in winter by means of electrical control. Therefore, the temperature of heat-collected air can be adjusted so as to be not too high in summer and to be corresponded with the desired temperature in winter.
In particular, in the case of the air type solar system having a heat-accumulating body which is comparatively free to the humidification target space or in the case of the system in the absence of such a heat-accumulating body, or in the case of the system by which the air is forced into the room such that the heated air is directly fed into the target space or the outside air is directly fed into the target space, the temperature of heat-collected air exerts a substantial influence upon the target space. Therefore, there is the need for adjusting the amount of airflow for adjusting the temperature of heat-collected air to the desired temperature, so that the control described above can be effective.
According to the invention, the air type solar system has another advantage of being preferable as an electric control in addition to the above advantageous actions.
According to the invention, the air type solar system is provided in combination with a damper having a gear-locking mechanism or the like to be fixed in a desired state even after powering off. Therefore, the dumper can be fixed in place without using any storage cell even though there is no electric power generated from the solar cells. Therefore, it becomes possible to prevent heat loss by an unexpected airflow and so on, allowing the control of operation suitable for self-sustaining.
According to the invention, the air type solar system can be controlled in an appropriate manner depending on circumstances by the use of a rewritable nonvolatile memory as a storage into which the contents of settings, the contents of detection by a temperature sensor, the contents of judgment by the controller, and so on. The information stored in the memory can be kept and rewritten without using any storage cell even after powering off.
According to the invention, the air type solar system is capable of supplying electric power, which can be generally used when the amount of solar radiation is small or when the system is operated in the night in general, by combining the power supply from the solar cells and the power supply from a commercially available power-supplying system.
Therefore, the solar cells are used in combination with an auxiliary power-supplying device being adjusted to a voltage lower than an operating voltage of the solar cells provided as the power source via a rectifying device. Almost the whole power generated from the solar cells is effectively used, while the auxiliary power-supplying device can be used in combination therewith to keep an appropriate voltage level. Therefore, the system can be operated with an acceptable amount of airflow in the night or darkness.
According to the invention, a solar system house can be realized.